Magazine fuse plug



Nov. 2s, 1933. o, F. OSS 1,937,406

MAGAZINE PLUG Filed March 24, 1930 2 Sheets-Sheet l Nov. 28, 1933. O, F- FOSS 1,937,406

MAGAZINE FUSE PLUG Filed March 24, 1930 2 Sheets-Sheet 2 Patented Nov. 28, 1933 UNITED STATES PATENT OFFICE MAGAZINE FUSE PLUG Application Marcil 24, 1930. Serial No. 438,285

12 Claims.

My invention relates to fuse plugs and has particular reference to the type wherein a plurality of fuses are suitably arranged in a magazine to permit the fuses to be selectively positioned in the electrical circuit of which the plug is a part.

The old type oi fuse plugs, wherein the plug contains but e. single fuse, requires a complete change of the plug when a fuse has become burned out. This necessitates the provision or" a quantity ol extra plugs in the vicinity of the fuse bor; which results in considerable trouble and, as a general rule, in the repeated confusion of used and unused plugs. There is also the inconvenience of being 'required to completely remove one plug and insert another and the constant tempn tation to employ a fuse plug of greater capacity in order to avoid this inconvenience.

My invention contemplates the pro'ision of a plug formed from insulating material and having a plurality of fuses radially placed therein to permit any one of the fuses to be brought into the electrical circuit by 'turning the cap of 'the plug. The plug is arranged to be rapidly and conveniently disassembled to permit the removal of burned out fuses and the replacement thereof with new fuses. The assembly is so arranged that the plug may not be disassembled until it has been removed from the fuse plug socket.

One of the objects of my invention is the pro-- vision oi a magazine fuse plug of simplified construction.

Another object of the invention is the p; ovision of simplified mea-ns for retaining the cap a magazine fuse plug onto the bottom or body portion thereof.

l have also to provide improved means for securing the fuses against movement in the fuse chmbers, and preventing arclng.

A still further object of the invention is to provide improved means for iorrnlng an contact between the iuse and the central oonductor of the plug.

A still further object or" the invention is 'to provide improved contacts for the lower end of the fuses whereby heating of the plug will be substantially avoided.

still further object oi the invention is the provision of a fuse plug assembly which may be i .lactured at a substantially lou-'M cost than tiros-o heretofore known.

Other objects and attendant advantages will become apparent as the discussion proceeds and by reference to the accompanying drawings in whichspring;

'7 is an elevation of a modified form of the plug shown partly in section to indicate the construction of the body portion;

Fig. 3 is a section on the line 8 3 of Fig. 7 showing the type of contact plate which may be employed when this structure is used; and

Fig. 9 is a section on the line 3 3 of Fig. l similar to that shown in Fig. 3 but showing a 7 Contact plate having 'out two sections.

Referring to Fig. l, the numeral 12 designates a cylindrical body portion formed of insulating material such as synthetic resin or porcelain. I prefer to use synthetic resin such as bakelite, though any insulating material which may be cast or molded may be employed to form this body portion. The body portion consists generalh7 of a lower cylindrical part 13 having screw threads 14 cast on the outer surface thereof and an upper cylindrical portion 15 integral there- The lower portion 13 is arranged to be in erted a fuse plug socket as will presently appear. The body l2 is provided with a central axially positioned opening 16 and a plurality of fuse chambers 17 radially positioned about this axial opening as shown in Fig. 2. The axial `opening 16 passes completely through the body portion while the fuse chambers 17 extend from the top o3? the portion l5 to a point slightly below the lower edge 18 thereof, passing a short disto -ce into the lower portion 13 as shown at 19. This provides an opening 20 from the exterior of the plug into each of the fuse chambers 17 at the lower end thereof. The openings 20 at the lower end of the chambers l? permit the insertion therein of contact plates 21 as shown in 3. These plates consist of three identical metallic plates having circular portions 22 arranged to move into the bottom of the chambers i7 shown in Fig. 3, a small portion of the circular part 22 being removed as shown at 23, to erniit the plate to pass the ribs 24 of the body portion l5 which separate the individual chambers. A metallic sleeve 25 having an upper flange 26 is arranged to engage the threads 14 of the lower portion 13 to bring the flange 26 firmly against the lower edge 18 of the upper portion 15, forcing the plates 21 into recesses 27 formed in the portion 15 for the reception thereoi. The sleeve 25 is adapted to be turned into the ius-e plug socket and provides one of the cor act points between the fuse plug and the societ, the sleeve having electrical contact with the :iu-ses through the plates 22. The sleeve 25 may be securely held in this position oy distorting the flange 26 into a notch 2S formed in the lower` edge of the portion 15. It will thus be seen that the flan e 26 holds the plates 21 against the lower edge of the body portion 15 to leave the space 19 between the plates and the portion i3. The upper portion l5 is provided near its edge with circumferential slot 29 adapted to receive a designated generally by 30. The upper portion 15 has an upstanding upper edge 3l adapted to bear against the 20 when the latter is drawn downward against the upper body portion. Vents or slots 32 may be provided at intervals on the circumference of the upstanding portion 31 to permit a certain amount of air to pass through the plug.

Fuses 33 are positioned in the ruse 17 so that their upper ends will project slightly above the level of the center portion 34 of the body 12. Ridges designated generally by the numeral 35 are caused to project from the upstanding riin 31 and extend inward between each of the fuse chambers 1'7. These ridges are provided with a high edge 36 and a low edge 37. The low edge 37 lies in the same or a lower horizontal plane than the upper end of the fuses 33 and the high edge 36 of the ridges l in a substantially higher plane than the top of the fuses thus providing inclined faces leading to the edges 36, which ends abruptly at the vs tical of the ribs, as clearly shown in Fig. 4.

The cap 30 is formed of the same insulating material as the body and is provided with downwardly projecting edges arranged to rest in the circumferential groove 29 of the body portion 12. The metal screw 39 is secured by casting or otherwise in the center of the cap and is arranged to engage the threaded portion 46 of a central rod 41 resting in the axial opening 16.

The lower end of the rod 41 is provided with a threaded portion 42 arranged to engage a metal. screw 43 having an enlarged head 44 arranged to bear against the lower end, 45 of the lower body portion 13 as shown in 1. It will. be seen that tightening the screw 43 the rod 4l may be drawn downward drawing the cap 30 down against the upstanding edge 31 of the upper body portion 15.

A U-shaped spring 46 shown more in detail in Fig. 6, is provided with a central opening 4'? through which the metal screw 39 is arranged to pass. The other side of the spring is provided with an opening 48 through which the central rod 4l is arranged to pass, the end of the rod 41 being screwed down tightly against the spring 46. The opening 48 is sufficiently large to permit the spring to move with respect thereto. Referring to Figs. 5 and 6, the spring 45 consists of a flat upper portion 49 having an opening 47 arranged to receive the metal screw 39 and a substantially at lower portion 50 connected to the upper portion through a U-bend 51. The upper portion 49 rests within a depression 46a in the cap 36, which prevents the spring from rotating with respect to the cap 30. The lower portion 50 is provided with a large central opening 48 through which the rod 41 is arranged tc pass. Positioned opposite the LI -bend 5l, is a horizontally extending contact brush 52 arranged to bear against the upper end ci the fuses 33 to provide electrical Contact therewith. The brush 52 may advantageously be formed integral with the portion 50 and is offset therefrom by a bend 50a in the metal. Ti end is such as to cause the brush 52 to lie substantially parallel with the portion 50 in a lower plane. As a result of the brush being placed in a lower plane the spring proper rests at a considerable distance from the top of the fuses 33, thus minimizing the danger of the current arcing between the spring and adjacent fuses. The shape of the spring also permits the pressure to be advantageously applied between the brush and the fuses. The forward edge 53 of the contact brush 52 is bent slightly upward to cooperate with the ridges 35 so that when the cap 3G is turned, the spring 46 turning therewith, the forward edge 53 of the contact brush 52 moves upward along the sloping sides of the next preceding ridge 35, causing the contact brush 52 to be lifted from contact with the upper end of the fuse. As movement of the top 30 is continued the Contact brush 52 moves up over the upper edge 36 or" the next succeeding ridge 35 and out over the end of the next succeeding fuse 33. Furmovement of the top 30 brings the rear edge 54 of the contact brush 52 off from the higher edge 35, causing it to snap down against the end of the fuse. This movement, because of the spring pressure on the brush 52, will be quick,

lili;

causing a rapid contact between the upper end of the fuse 33 and the Contact brush 52 of the spring and permitting only a minimum amount of sparking therebetween when the Contact is made.

The cap 30 is provided with a circular downwardly extending ring 55 so positioned as to bear against the inner edges of all o the fuses 33 at the top end thereof except that against which the brush 52 rests, the spring passing through the space 33' in the ring 55 to permit the brush to reach the fuses. This holds cach of the fuses firmly in its place and permits the fuse plug to be inserted upside down, for instance, into a socket positioned on a ceiling or the like, without the fuses moving endwise in the chambers 17 and thus interfering with the operation of the plus. The rim 55 forms a central depression 55a wi in which the spring is supported. This serves to minimize the danger of arcing of the current between the spring and the top of the fuses 33. However, the length of the fuses 33 may vary and in order to permit a certain amount of resiliency between the ring 55 and the fuses 33 the plates 21 are spaced, as at 19, from the upper end oi the lower portion 13. It will be seen that if one of the fuses 33 is slightly longer than the others, when the metal screw 43 tightened, drawing the cap 30 downward against the upstanding edge 3l, the projection 55 will bear first against the longest of these fuses. However, with continued tightening of the screw 43, this longer fuse will. be forced downward slightly, springing the plate 21 to accommodate this extra length.

Referring to Fig. 9, I have shown a modica- 'tion in which the Contact plate is formed of only two portions 56 instead of the three portions shown in Fig. 3. Sections 57 are cut from the plate similar to sections 23 to permit the plates to be inserted through the openings 20.

the lower end 13 of the body portion and the upper end 15 thereof, are separately formed. In

this case the upper portion 15 is provided with a downwardly` projecting sleeve 58 around the axial rod 41 having flattened sides 62. The lower portion 13 is provided with a complementary opening 59 arranged to receive the sleeve 58 and nt closely thereto. It will be seen that when the metal screw 43 is tightened, the portion 13 will be drawn closely against the portion 15 and the parts will be securely held together. Such a construction of the body portion 12 permits a circular contact plate 60 to be employed. This plate 60 may be a flat sheet of metal having a circular central opening 61 for the reception of the sleeve 58 and which may be inserted between the lower portion 13 and the upper portion 15 of the body by removing the screw 43 and removing the lower portion 13 from the sleeve 58.

In order that the operator may know the fuse upon which the Contact brush 52 is resting at any particular time a plurality of ribs 63 are provided on the outer surface of the body 12 opposite each of the fuse chambers 17. One of these ribs, may be longer than the others, as shown at 64 to provide a reference point or the ribs may be numbered. The cap 30 is provided with a single rib 65 opposite the contact brush 52 to indicate its position. The operator may thus know at a glance the number of fuses which have been used or the number remaining.

The fuse plug is adapted to be inserted into the conventional fuse plug socket, the sleeve 25 engaging the threaded portion thereof and forming electrical contact between the plug and socket. When the plug is properly positioned the head 44 of the metal screw 43 will bear against the center of the socket to form the second connection between the plug and socket in the usual manner. The current will then pass through the fuse plug in the conductors formed by the metal screw 43, the rod 41, spring 46, contact brush 52, fuse 33, contact plates 21, and metal sleeve 25. When any one of the fuses 33 are burned out the top 30 is turned in a clockwise direction. Movement ofthe top moves the Contact brush 52 onto the succeeding ridge 35 and subsequently to the top of a succeeding fuse 33. The electrical contacts otherwise remain undisturbed, the central rod 41 and screw 43 turning in the opening 16. When the top 30 is turned in a clockwise direction, both of the screws 39 and 43 have a tendency to tighten when provided with the usual screw threads, and therefore, will not loosen when the plug is in use. They may, however, be very readily loosened when the plug is removed from its socket.

It will be seen that I have provided a highly improved magazine fuse plug. The mechanism is very simple. The central rod 41 extends completely through the body 12 and is attached to the top 30 through the metal screw 39. The large head 44 of the metal screw 43 bears against the shoulder 45 of the body 12 and prevents the topv from being tightened against the body bei yond a certain point; thus insuring a uniform v'the fuses 33 are maintained in the same hori- Zontal plane. This has been one of the major difficulties of the plugs of the prior art, the irregularities in the fuses causing the top 30 to turn at times with difculty and at other times causing the end 52 of the contact spring 46 to fail to make contact.

The method of positioning the lower contact plates 21 permits suii'icient resiliency in the sup port of the fuses 33 to compensate for any irregularities in the length of the fuses permitting the ring to bring the tops of all of the fuses into the same plane. This construction also permits the fuse plug to be made at a substantial saving in manufacturing costs.

The plug is arranged to provide maximum safety in use. Access may not be had to the interior of the plug or to the fuses until it has been removed from the socket. When the plug is removed froin the socket it is merely necessary to remove the screw 43 from the rod 41 and the top may be removed from the body by drawing the rod from the opening 16. When the cap is so removed and the body 12 inverted the fuses will drop from the chambers 17 of their own weight and new fuses may be easily inserted.

It will be seen that the simplicity of the manner in which the cap 30 is rotatably and releasably secured to the body 12 results in a plug of superior operation and a substantially lower priced plug, in which the contact spring 46 is so shaped and designed as to result in marked enciency in its contact making power. The construction is further such that no additional spring member is required to bring about suitable contact between the upper end of the fuses 33 and the contact end 52 of the spring.

t will further be seen that the ridges 35 are so constructed as to permit the projection 55 to bear against the inner edges of the fuses and also to permit the contact end 52 of the spring 46 to make a rapid and positive contact with the fuses 33.

The contact points 52 and the ridges 35 are so arranged as to prevent the cap 30 from being turned in a reverse direction, as will be seen from Fig. 4. This permits the operator to remove the fuse plug from the socket by grasping the cap 30 of the plug and turning in a counter clockwise direction.

While I have thus described and illustrated a specific embodiment of my invention I am aware that numerous alterations and changes may be made therein without materially departing from the spirit of the invention and I do not wish to l be limited except as required by the prior art j' y and the scope of the appended claims in which- I claim: 1. In a magazine fuse plug, a body having a lower end formed to be turned into a socket, an

axial opening and a plurality of chambers radially jg 3 spaced therefrom, cartridge fuses position in said chambers, a central rod of electrically conductive material positioned in said axial opening, a cap axially attached to said central rod arranged to cover the upper end of said body and spaced from t.;

said fuses, means, releasable only when said plug is removed from said socket, attached to the lower end of said central rod and exposed at the lower end of said body for rotatably securing said rod and cap thereto, means on saidY cap arranged to bear against said fuses to prevent endwise movement thereof.

2. In a magazine fuse plug, a one-piece body of insulating material, having a threaded lower portion adapted to be inserted in a socket and an upper portion arranged to project therefrom, said body having an axial. opening and a plurality of chambers spaced therefrom, fuses positioned within said chamber, at least one plate of electrically conductive material arranged to be inserted between said threaded lower portion and said upper portion and to project across a substantial part of said chambers to provide a conducting support of wide area for each of said fuses, means positioned on said threaded lower portion to hoid said plate in position and provide an electrical contact between said plate and said socket, a cap positioned over the outer edge of said upper portion, arranged to enclose said fuses, means to secure the fuse against endwise movement within said chamber, electrically conductive means positioned in said axial opening adapted to secure said cap to said body and provide a central electrical contact with said socket, and means between said cap and said body for electrically connecting said fuses with said last mentioned means whereby the electrical current is caused to flow through any one of said fuses.

3. In a magazine fuse plug, a body of insulating material having a. threaded lower portion adapted to be inserted in a socket and an upper portion arranged to project therefrom, body having an axial opening and a plurality of chambers radially spaced therefrom, fuses positioned within said chamber, a circular plate of conductive metal divided into three sections and having projections arranged to project into said chambers to substantially cover the bottom thereof, providing a support for each of said fuses, means positioned on said threaded lower portion to hold said plate in position and provide an electrical contact between said plate and said socket, a cap positioned over the outer end of said upper portion, arranged to enclose said fuses, means to secure the fuses against endwise movement within said chamber, electrically conductive means positioned in said axial opening adapted to secure said cap to said body and provide a cen tral electrical contact with socket, and means between said cap and said body for selectively connecting said fuses with said last mentioned means 'whereby the electrical current may be caused to pass through any one of said fuses.

4. In a magazine fuse plug, a body of insulating material having a threaded lower portion adapted to be inserted in a socket and an upper portion arranged to project therefrom, said body having an axial opening and a plurality of chambers radially spaced therefrom, cartridge fuses removably positioned within said chambers, electrical conductors between the lower end of said fuses and one terminal of said socket, a rod positioned within said axial opening and arranged at its lower end to provide a central electrical contact with a second terminal of said socket, a cap of insulating material positioned over the outer end of body enclosing the upper f said fuses, means on said cap for preventing endwise movement of said fuses, a screw secured within said cap having threaded engagement with the upper end of said rod, said cap and said rod having axial movement together within said body for selectively contacting with said fuses, a brush spring, having an upper portion reieasably held between said screw and said rod and secured against rotation within said cap, and a lower portion having an opening to receive said rod, a brush integral with said lowerV portion and arranged to be urged against the end of said fuses thereby, ridges in said body between said chambers, said ridges causing said brush to be lifted free from one fuse, upon rotation of said cap, and be snapped downward under the action of said spring against the next succeeding fuse, and

means for preventing said cap from being ro tated in more than one direction.

5. In a magazine fuse plug, a body oi insulating material having a threaded lower portion adapted to be inserted into a socket and an upper portion arranged to project therefrom, said body having a circular upstanding outer edge, an axial opening, and a plurality of chambers radially spaced therefrom within said body, cartridge fuses removably positioned within said chambers, electrical conductors between the lower end of said fuses and one terminal of said socket, a rod of electrically conductive material rotatably positioned within said axial opening, a cap positioned over the outer end of said body adapted to rotatably receive said upstanding edge to enclose the ends of said fuses, said rod being iixedly attached thereto, a screw arranged to bear against the lower end of said threaded lower` portion and engage said rod to maintain said cap against said upstanding edge, provide an electrical contact between rod and a second terminal of said socket, means for preventing rotation of said cap in a direction to loosen said screw to prevent the removal of said cap when said plug is in said socket, and means attached to said rod for selectively and progressively providing an electrical contact between the upper end of said fuses and said rod, when said cap is rotated, whereby any one of said fuses may be positioned between the terminals of said socket.

5. The combination, in a magazine fuse plug, of a spring of flat strap metal having substantially parallel upper and lower portions, a U- shaped connecting portion, and a brush attached to one end of said lower portion substantially parallel thereto and in a lower plane, with a. cap having a circular ring of insulating material forming a recess adapted te receive said upper portion to prevent the same from rotation therein and prevent arcing between said upper portion and adjacent fuses and a rod axially secured to said cap to hold said spring within said recess.

7. The combination, in a magazine fuse plug, adapted to be positioned in a socket, of a body having an axial opening, with a cap arranged to be positioned over one end of said body, and a cylindrical rod xedly attached to said cap arranged to pass through said axial opening and be free to rotate therein, and releasable means, releasable only when said plug is removed from said socket, acting between said rod and a second end of said body, for securing said rod Within said opening.

8. The combination, in a magazine fuse plug of a body of insulating material having an end receivable'in a socket and an axial opening, with a cap of insulating material arranged to rest over the opposite end of said body, a metal screw axially secured in said cap, a cylindrical rod adapted to receive said metal screw at one end thereof, and to rotatably rest within said axial opening, and a metal screw adapted to be received in the opposite end of said rod and bear against the opposite end of said body to releasably secure said rod within said opening. to draw said cap against said body and to prevent removal thereof when said plug is positioned in said socket.

9. The combination, in a magazine fuse plug,

of a body of insulating material having an axial opening, radially spaced fuse chambers, and fuses positioned within said chambers, with a cap positioned over one end of said body covering one end or" said chambers, a cylindrical rod axially attached to said cap arranged to pass through said opening and be free to rotate therein, a spring secured between said cap and said rod arranged to successively Contact with said fuses, a ring on said cap around said spring to prevent endwise movement of said fuses and prevent electrical contact between said spring and more than one of said fuses, and releasable means acting between said rod and a second end of said body for securing said rod within said opening.

10. A magazine fuse plug comprising in comn bination, a body of insulating material having a plurality of chambers radially spaced therein, a cap of insulating material rotatably positioned over one end of said chambers, cartridge fuses removably positioned in said chambers, spring contact means on said cap for making electrical contact with the end of said fuses, ridges in said body between said chambers for lifting said contact means free from one fuse, upon rotation of said cap, and releasing said means to be snapped downward under the action of the spring against the next succeeding fuse. and means on said cap for securing said fuses from endwise movement and preventing the iiow of current between said contact means and adjacent fuses.

insulating material rotatably positioned over one end of said chambers, cartridge fuses removably positioned in said chambers, spring contact means on said cap for making electrical contact with the end of said fuses, ridges in said body between said chambers for lifting said contact means free from one fuse, upon rotation oi said cap, and releasing said means to be snapped downward under the action of the spring against the next succeeding fuse, means on said cap for securing said fuses from endwise movement and preventing the iiow of current between said contact means and adjacent fuses, and releasable means acting between said cap and the inner end of said body for holding said cap in position, said last-mentioned means being accessible only when said plug is removed from said socket to prevent said cap from being removed when said plug is in position in said socket.

l2. A magazine fuse plug comprising in combination, a body oi insulating material having a plurality of radially spaced chambers therein, cartridge fuses removably positioned within said chambers, a cap of insulating material positioned at the end of said body to enclose one end of said fuse, spring contact means on said cap for electrical contact with the end of said fuses, radial ridges extending only part way between said chambers, said ridges causing said contact means to be lifted free from one fuse, upon rotation of said cap, and be snapped downward against the nent succeding fuse, and a ring of insulating material on said cap bearing against the ends of said fuses, to prevent endwise movement thereof within the chambers.

OSCAR FREDERICK FOSS. 

